[linux-audio-user] Device for simple stereo dubbing?

[Clemens Ladisch]

Joseph Zitt wrote:
> Could it be a problem with the UA-30 refusing to return config
> descriptor 0, whatever that is, when the program asks for it?

No, the kernel does successfully get the descriptors. The contents of
/proc/bus/usb/001/00X are obviously :-) correct.

> The closest thing I've seen to documentation of the config descriptors
> is at
> http://www.beyondlogic.org/usbnutshell/usb5.htm##ConfigurationDescriptors
> (yes, two # signs are needed), but I'm not following what this means.

The various descriptors are described in the various USB
specifications which you can find at www.usb.org, but trust me: you
don't want to read them.

In short, the descriptors tell the driver about the capabilities of
the device.

> > [root at localhost Documents]# od -t x1 /proc/bus/usb/001/003
> > 0000000 12 01 00 01 00 00 00 08 82 05 06 00 10 01 01 02
> > ...
> > Wow, that was immediately informative! :-)
>
> Digging around, I haven't been able to find information that I
> understand as to what this tells us. Could someone offer and
> interpretation, and what it lets us know about the error?

This is exactly the same information as in the output of lsusb, only
without those bothersome labels.

The UA-30 actually seems to have 100% standard-conforming descriptors,
so the driver ought to work with it (well, in theory).


Does your computer still blow up when you unload all ALSA modules and
do a "modprobe audio"?


> > Clemens Ladisch wrote:
> >>>> Please try
> >>>> a more recent ALSA version, there have been some changes to the
> >>>> snd-usb-audio driver since then.
>
> Looking at the errors below, it looks like the appropriate thing would
> be to completely remove alsa and reinstall it -- though that also may be
> inappropriate and catastrophic, depending on what's depending on it. Any
> clues?

Yes, please remove _all_ old ALSA packages before installing the new
ones.


HTH
Clemens